Logic Elaborated: An Account of the Source of the Normativity of Logic

The idea that logic has a normative role to play in our lives by telling us what we should and shouldn’t believe is well-entrenched in both philosophical tradition and our ordinary thinking about logic. In my dissertation, I focus on the question of the source of the normativity of logic – that is, why should we (on the assumption that we indeed should) heed the advice of logic? In the first part of the dissertation, I argue against the standard answer this question. I call it the “extrinsic view”. This view holds that (1) logic is to be understood as entirely independent from how we think and reason; and (2) the source of the normativity of logic lies in certain normative facts about belief – most notably that belief aims at truth. I argue against both components of the view, claiming, first, that the most well-established candidates for a definition of validity face serious philosophical challenges; and, second, that the idea that belief aims at truth is not fit to vindicate the full range of normative roles that we take logic to play. In the second part of the dissertation, I turn to an assessment of whether an alternative view can be rendered intelligible and defended. According to what I call the “intrinsic view”, logic is itself a normative enterprise. I defend a pragmatic constitutivist interpretation according to which logic is in the business of laying out (formally – in some sense of formal to be clarified) the norms that constitutively govern our believing practices. I examine one of the most serious stumbling blocks against the constitutive component of the view, namely, the possibility of error. I argue that constitutivism is entirely consistent with certain kinds of logical error, even though there are other kinds which it rules out. I then offer a sketch of how logic could be understood as formally laying out certain features of our believing practices. This suggests pluralism about logic, i.e., the idea that there is more than one correct logic. I argue that there is no tension between pluralism and the constitutive component of the proposal.